Acute tonsillitis is an acute infectious inflammation of the tonsils, primarily caused by bacterial infection, though it often also involves viral infection. Acute tonsillitis is mildly contagious; the contagion is not severe or serious, and general isolation is not necessary. It is sufficient to take some precautions in daily life, such as avoiding kissing and the mouth-to-mouth transfer of food. Generally speaking, the contagiousness of acute tonsillitis is relatively weak. Appropriate use of a mask for local isolation, such as wearing a mask to prevent transmission, is sufficient without the need for other special treatments.